<template>
  <input type="file" name="pic" ref="file" accept="image/*" @change="upload"/>
</template>

<script>
import Exif from "exif-js";
import { upload } from "@/api";

export default {
  props: {
  },
  data() {
    return {
      uploadName: ""
    };
  },
  mounted() {
    console.log(this.uploadType);
  },
  methods: {
    upload(e) {
      if (e.target.files.length > 0) {
        this.$vux.loading.show("Loading...");
        let files = e.target.files || e.dataTransfer.files;
        if (!files.length) return;
        this.picValue = files[0]
        this.uploadName = files[0].name;

        // 上传图片
        var u = navigator.userAgent, app = navigator.appVersion;
        var isAndroid = u.indexOf('Android') > -1 || u.indexOf('Linux') > -1; //g
        var isIOS = !!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/); //ios终端
        if (isAndroid) {
          this.axiosFun(this.picValue);
        }
        if (isIOS) {
    　　　this.imgPreview(this.picValue);
        }

        // 上传视频
        // this.axiosFun(this.picValue);
      }
    },
    imgPreview(file) {
      let self = this;
      let Orientation;
      //去获取拍照时的信息，解决拍出来的照片旋转问题
      Exif.getData(file, function() {
        Orientation = Exif.getTag(this, "Orientation");
      });
      // 看支持不支持FileReader
      if (!file || !window.FileReader) return;

      if (/^image/.test(file.type)) {
        // 创建一个reader
        let reader = new FileReader();

        // 将图片2将转成 base64 格式
        reader.readAsDataURL(file);

        // 读取成功后的回调
        reader.onloadend = function() {
          let result = this.result;
          let img = new Image();
          img.src = result;
          //判断图片是否大于100K,是就直接上传，反之压缩图片
          if (this.result.length <= 100 * 1024) {
            self.headerImage = this.result;
            self.postImg();
          } else {
            img.onload = function() {
              let data = self.compress(img, Orientation);
              self.headerImage = data;
              self.postImg();
            };
          }
        };
      }
    },
    compress(img, Orientation) {
      let _this = this
      let canvas = document.createElement("canvas");
      let ctx = canvas.getContext("2d");
      //瓦片canvas
      let tCanvas = document.createElement("canvas");
      let tctx = tCanvas.getContext("2d");
      let initSize = img.src.length;
      let width = img.width;
      let height = img.height;
      //如果图片大于四百万像素，计算压缩比并将大小压至400万以下
      let ratio;
      if ((ratio = width * height / 4000000) > 1) {
        console.log("大于400万像素");
        ratio = Math.sqrt(ratio);
        width /= ratio;
        height /= ratio;
      } else {
        ratio = 1;
      }
      canvas.width = width;
      canvas.height = height;
      //        铺底色
      ctx.fillStyle = "#fff";
      ctx.fillRect(0, 0, canvas.width, canvas.height);
      //如果图片像素大于100万则使用瓦片绘制
      let count;
      if ((count = width * height / 1000000) > 1) {
        console.log("超过100W像素");
        count = ~~(Math.sqrt(count) + 1); //计算要分成多少块瓦片
        //            计算每块瓦片的宽和高
        let nw = ~~(width / count);
        let nh = ~~(height / count);
        tCanvas.width = nw;
        tCanvas.height = nh;
        for (let i = 0; i < count; i++) {
          for (let j = 0; j < count; j++) {
            tctx.drawImage(
              img,
              i * nw * ratio,
              j * nh * ratio,
              nw * ratio,
              nh * ratio,
              0,
              0,
              nw,
              nh
            );
            ctx.drawImage(tCanvas, i * nw, j * nh, nw, nh);
          }
        }
      } else {
        ctx.drawImage(img, 0, 0, width, height);
      }
      //修复ios上传图片的时候 被旋转的问题
      if (Orientation != "" && Orientation != 1) {
        switch (Orientation) {
          case 6: //需要顺时针（向左）90度旋转
            _this.rotateImg(img, "left", canvas);
            break;
          case 8: //需要逆时针（向右）90度旋转
            _this.rotateImg(img, "right", canvas);
            break;
          case 3: //需要180度旋转
            _this.rotateImg(img, "right2", canvas);
            break;
        }
      }
      //进行最小压缩
      let ndata = canvas.toDataURL("image/jpeg", 0.1);
      tCanvas.width = tCanvas.height = canvas.width = canvas.height = 0;
      return ndata;
    },
    rotateImg(img, direction, canvas) {
      //最小与最大旋转方向，图片旋转4次后回到原方向
      const min_step = 0;
      const max_step = 3;
      if (img == null) return;
      //img的高度和宽度不能在img元素隐藏后获取，否则会出错
      let height = img.height;
      let width = img.width;
      let step = 2;
      if (step == null) {
        step = min_step;
      }
      if (direction == "right") {
        step++;
        //旋转到原位置，即超过最大值
        step > max_step && (step = min_step);
      } else if (direction == "right2") {
        step = 2;
      } else {
        step--;
        step < min_step && (step = max_step)
      }
      //旋转角度以弧度值为参数
      let degree = step * 90 * Math.PI / 180;
      let ctx = canvas.getContext("2d");
      switch (step) {
        case 0:
          canvas.width = width;
          canvas.height = height;
          ctx.drawImage(img, 0, 0);
          break;
        case 1:
          canvas.width = height;
          canvas.height = width;
          ctx.rotate(degree);
          ctx.drawImage(img, 0, -height);
          break;
        case 2:
          canvas.width = width;
          canvas.height = height;
          ctx.rotate(degree);
          ctx.drawImage(img, -width, -height);
          break;
        case 3:
          canvas.width = height;
          canvas.height = width;
          ctx.rotate(degree);
          ctx.drawImage(img, -width, 0);
          break;
      }
    },
    postImg() {
      //这里写接口
      // console.log(this.headerImage)
      const block = this.headerImage.split(";");

      const contentType = block[0].split(":")[1]; // In this case "image/jpeg"

      const realData = block[1].split(",")[1]; // In this case "R0lGODlhPQBEAPeoAJosM...."

      var blob = this.b64toBlob(realData, contentType);
      this.axiosFun(blob);
    },
    uploadDefined(file, data, callback) {
      let _this = this;
      let gObjectName = data.dir + this.randomString() + this.getSuffix(this.uploadName);
      let request = new FormData();
      request.append("OSSAccessKeyId", data.accessid); // Bucket 拥有者的Access Key Id。
      request.append("policy", data.policy); // policy规定了请求的表单域的合法性
      request.append("Signature", data.signature); // 根据Access Key Secret和policy计算的签名信息，OSS验证该签名信息从而验证该Post请求的合法性
      request.append("key", gObjectName); // 文件名字，可设置路径
      request.append("success_action_status", "200"); // 让服务端返回200,不然，默认会返回204
      request.append("x-oss-object-acl", "public-read");
      request.append("file", file);

      let xhr = new XMLHttpRequest();
      xhr.open("POST", data.host);
      xhr.send(request);
      xhr.onreadystatechange = function() {
        if (xhr.readyState === 4 && xhr.status === 200) {
          // console.log("fileKey => " + data.host + "/" + gObjectName);
          // console.log(_this.imgPaths);
          _this.$vux.loading.hide();                
          callback(data.host, gObjectName);
        } else if (xhr.status === 400){
          _this.$vux.loading.hide();
          _this.$vux.toast.text('图片太大,请换取小的图片')
        }
      };
    },
    async imgUpload(){
      // const { data } = await uploadImg({url: host, })
    },
    async axiosFun(blob) {
      let that = this;
      const { data } = await upload({});

      that.uploadDefined(blob, data, function(host, name) {
        that.$emit("uploadImage", {
          value: host + "/" + name,
        });
      });
    },
    randomString(len) {
      len = len || 32;
      var chars = "ABCDEFGHJKMNPQRSTWXYZabcdefhijkmnprstwxyz2345678";
      var maxPos = chars.length;
      var pwd = "";
      for (var i = 0; i < len; i++) {
        pwd += chars.charAt(Math.floor(Math.random() * maxPos));
      }
      return pwd;
    },
    getSuffix(filename) {
      var pos = filename.lastIndexOf(".");
      var suffix = "";
      if (pos !== -1) {
        suffix = filename.substring(pos);
      }
      return suffix;
    },
    b64toBlob(b64Data, contentType = "", sliceSize = 512) {
      const byteCharacters = atob(b64Data);
      const byteArrays = [];

      for (
        let offset = 0;
        offset < byteCharacters.length;
        offset += sliceSize
      ) {
        const slice = byteCharacters.slice(offset, offset + sliceSize);

        const byteNumbers = new Array(slice.length);
        for (let i = 0; i < slice.length; i++) {
          byteNumbers[i] = slice.charCodeAt(i);
        }

        const byteArray = new Uint8Array(byteNumbers);

        byteArrays.push(byteArray);
      }

      const blob = new Blob(byteArrays, { type: contentType });
      return blob;
    }
  }
};
</script>

<style>
</style>